Rover refuses to successfully change modes in Version 4

Now running version 4 ( I believe 4.1.1 ) in my Rover.
But unlike version 3, it balks at changing modes saying " Mode Change Failed"
Any clues??

Having the same issue running Cube with stable 4.0 Rover. No pre-arm issues, GPS good, EKF happy and wont go into Auto mode. Says flight mode change failed in Mission Planner (running latest beta). Then booted up Qgroundcontrol and that worked a treat, let me change to Auto.

Does yours work with QGC?


Heh Nik221,
Yes it works with QGC actually much better than Mission Planner. As soon as I plug it in , I get 8 or 9 additional sensors. Most of which are giving me acceptably/really accurate speeds, headings, amps, etc.

Here is the beast:

But the url does not show ???

@jwcalvert, @Nik221,

If you can provide an onboard log that would be good.

It’s very unlikely that the ability to change modes is related to the ground station being used. It’s much more likely that it’s an environmental issue - for example the quality of the GPS, the amount of interference on the compas from power wires below it, etc.

I think we are mixing two different issues here. My first issue was that the rover will not successfully change modes. I agree, that is not likely to be caused by the ground control software. However with version 3, the rover would change modes in my basement with no GPS at all. Something is different here.
My second issue was that the new cable connecting the Pixhawk to a FrSky X8R receiver gives me only a GPS sensor on Mission Planner, but several more as well on QGC. I find that odd.


OK, re not being able to switch into Auto mode when disarmed I think this is the issue. Basically some extra arming checks were added into Rover-4.0 and they are overly strict. Basically we should always be able to change into any mode when the vehicle is disarmed.

@rmackay9 thanks for the update - yes I think this was my issue in Mission Planner.


I did the following:

  1. Loaded up the latest v4.0.1-dev firmware

  2. This did not resolve the mode change failure

At that time it had a good compass and a good GPS with 8 sats.

  1. It still would not allow the MP to change ARM to DISARM at all.

  2. Loaded up the Copter v4.0.2

  3. From the MP ACTION feature

Set mode now works

ARM/DISARM now works

  1. But the Rover was obviously undriveable.

  2. Log is here:

I hope you see what is wrong because I have no clues.


Jim Calvert

I have just now gotten back to the Rover and the ARM issue and Failure to change flight mode issue still exists.
Is there any hope someone can fix this please?